1. Field of the Invention
The present invention relates to a cover apparatus of a machine tool that separates a processing space, in which a workpiece is processed, and a setup space, in which setup for the processing is performed, from each other.
2. Description of the Related Art
A known machining center includes a first cover and a second cover that are arranged in a vertical positional relationship, between a processing space and a setup space. In this structure, the two spaces are partitioned during the processing of a workpiece by holding the first and second covers in a lowered state. To interchange the workpieces between the two spaces, for example, the first and second covers are held in a raised state.
In the above-described structure, the first and second covers are connected to different drive sources via different up-down movement mechanisms. Therefore, it is necessary to determine the time to drive each of the two drive force sources based on output signals from sensors. Hence, the possibility of a malfunction increases, and reliability decreases.
Accordingly, it is an object of the present invention to provide a cover apparatus of a machine tool that achieves high reliability.
In accordance with the present invention, a cover apparatus of a machine tool includes a first cover provided between a processing space, in which a workpiece is processed, and a setup space, in which a setup for a processing of the workpiece is performed, a second cover that is provided below the first cover, and that separates the processing space and the setup space from each other in cooperation with the first cover, an up-down movement mechanism that moves the first cover and the second cover upward and downward, a pivoting mechanism that pivots the second cover, and a drive force source that generates a drive force for the up-down movement mechanism and the pivoting mechanism.
In the above-described cover apparatus, the first cover and the second cover are connected to the single drive force source via the single up-down movement mechanism. Therefore, it becomes unnecessary to synchronize the drive times for a plurality of drive force sources based on output signals of sensors. Hence, the cover apparatus prevents deviations of the up-down movement timing of the first cover and the up-down movement timing of the second cover, thereby improving reliability.
The cover apparatus of a machine tool may further have a structure as described below. That is, the drive force source is formed by one drive portion, and the up-down movement mechanism and the pivoting mechanism are connected to the drive force source via a cam mechanism that transmits the drive force from the drive force source to the up-down movement mechanism and the pivoting mechanism at a set timing.
With this structure, the up-down movements of the first and second covers and the pivoting of the second cover are achieved by the single drive force source. Therefore, the need for a dedicated drive force source to pivot the second cover is eliminated, thereby allowing simplification of the structure. Furthermore, it becomes unnecessary to synchronize the drive time of a drive force source to move the first and second covers up and down and the drive time of a drive force source to pivot the second cover with each other based on output signals of sensors. Hence, the cover apparatus prevents deviations of the up-down movement timing of the first and second covers and the pivoting timing of the second cover, thereby further improving reliability.
The cover apparatus of a machine tool may further have a structure as described below. That is, the cam mechanism includes a first cam drive portion that transmits the drive force from the drive force source to the up-down movement mechanism so that the first cover and the second cover are held in a raised state, and a second cam drive portion that transmits the drive force from the drive force source to the pivoting mechanism when the first cover and the second cover are held in the raised state. The pivoting mechanism is connected to a workpiece changing arm that changes workpieces between the processing space and the setup space by pivoting below the second cover when the first cover and the second cover are raised.
Therefore, when the second cover is pivoted while the first and second covers are in the raised state, the workpiece changing arm interchanges the workpiece in the setup space and the workpiece in the processing space by pivoting together with the second cover. Since the up-down movement timing of the first and second covers is set by the dedicated first cam drive portion, and the pivoting timing of the second cover and the workpiece changing arm is set by the dedicated second cam drive portion, the cover apparatus prevents deviations of the up-down movement timing of the first and second covers, the pivoting timing of the second cover, and the pivoting timing of the workpiece changing arm, thereby further improving reliability.
Still further, in the cover apparatus of the invention, the up-down movement mechanism may have a lever to operate the first cover and the second cover. The lever overlaps a lower end portion of the first cover and an upper end portion of the second cover with each other when the first cover and the second cover are in a lowered state, and the lever separates the first cover and the second cover from each other when the first cover and the second cover are in the raised state.
Since the lower end portion of the first cover and the upper end portion of the second cover overlap each other when the first and second covers are in the lowered position, the cover apparatus prevents processing debris and the like from traveling from the processing space into the setup space via a gap between the first and second covers. Furthermore, since the overlap of the lower end portion of the first cover and the upper end portion of the second cover is discontinued when the first and second covers are in the raised state, the cover apparatus prevents the first cover from interfering with the second cover when the second cover is pivoted while the first and second cover are in the raised state.